Remove mjs support (#5027)

* Revert Lerna dependency, there's too many bugs in v3

* Remove `mjs` support

Author: Timer

packages/react-scripts/config/webpack.config.dev.js

@@ -142,7 +142,7 @@ module.exports = {
     // https://github.com/facebook/create-react-app/issues/290
     // `web` extension prefixes have been added for better support
     // for React Native Web.
-    extensions: ['.web.js', '.mjs', '.js', '.json', '.web.jsx', '.jsx'],
+    extensions: ['.web.js', '.js', '.json', '.web.jsx', '.jsx'],
     alias: {
       // @remove-on-eject-begin
       // Resolve Babel runtime relative to react-scripts.
@@ -175,7 +175,7 @@ module.exports = {
       // First, run the linter.
       // It's important to do this before Babel processes the JS.
       {
-        test: /\.(js|jsx|mjs)$/,
+        test: /\.(js|jsx)$/,
         enforce: 'pre',
         use: [
           {
@@ -214,7 +214,7 @@ module.exports = {
           // Process application JS with Babel.
           // The preset includes JSX, Flow, and some ESnext features.
           {
-            test: /\.(js|jsx|mjs)$/,
+            test: /\.(js|jsx)$/,
             include: paths.appSrc,
             use: [
               // This loader parallelizes code compilation, it is optional but
@@ -341,7 +341,7 @@ module.exports = {
             // its runtime that would otherwise be processed through "file" loader.
             // Also exclude `html` and `json` extensions so they get processed
             // by webpacks internal loaders.
-            exclude: [/\.(js|jsx|mjs)$/, /\.html$/, /\.json$/],
+            exclude: [/\.(js|jsx)$/, /\.html$/, /\.json$/],
             loader: require.resolve('file-loader'),
             options: {
               name: 'static/media/[name].[hash:8].[ext]',

packages/react-scripts/config/webpack.config.prod.js

@@ -180,7 +180,7 @@ module.exports = {
     // https://github.com/facebook/create-react-app/issues/290
     // `web` extension prefixes have been added for better support
     // for React Native Web.
-    extensions: ['.web.js', '.mjs', '.js', '.json', '.web.jsx', '.jsx'],
+    extensions: ['.web.js', '.js', '.json', '.web.jsx', '.jsx'],
     alias: {
       // @remove-on-eject-begin
       // Resolve Babel runtime relative to react-scripts.
@@ -213,7 +213,7 @@ module.exports = {
       // First, run the linter.
       // It's important to do this before Babel processes the JS.
       {
-        test: /\.(js|jsx|mjs)$/,
+        test: /\.(js|jsx)$/,
         enforce: 'pre',
         use: [
           {
@@ -253,7 +253,7 @@ module.exports = {
           // Process application JS with Babel.
           // The preset includes JSX, Flow, and some ESnext features.
           {
-            test: /\.(js|jsx|mjs)$/,
+            test: /\.(js|jsx)$/,
             include: paths.appSrc,
             use: [
               // This loader parallelizes code compilation, it is optional but
@@ -375,7 +375,7 @@ module.exports = {
             // it's runtime that would otherwise be processed through "file" loader.
             // Also exclude `html` and `json` extensions so they get processed
             // by webpacks internal loaders.
-            exclude: [/\.(js|jsx|mjs)$/, /\.html$/, /\.json$/],
+            exclude: [/\.(js|jsx)$/, /\.html$/, /\.json$/],
             options: {
               name: 'static/media/[name].[hash:8].[ext]',
             },

packages/react-scripts/scripts/utils/createJestConfig.js

@@ -21,42 +21,34 @@ module.exports = (resolve, rootDir, isEjecting) => {
   // TODO: I don't know if it's safe or not to just use / as path separator
   // in Jest configs. We need help from somebody with Windows to determine this.
   const config = {
-    collectCoverageFrom: ['src/**/*.{js,jsx,mjs}'],
+    collectCoverageFrom: ['src/**/*.{js,jsx}'],
     setupFiles: [resolve('config/polyfills.js')],
     setupTestFrameworkScriptFile: setupTestsFile,
     testMatch: [
-      '<rootDir>/src/**/__tests__/**/*.{js,jsx,mjs}',
-      '<rootDir>/src/**/?(*.)(spec|test).{js,jsx,mjs}',
+      '<rootDir>/src/**/__tests__/**/*.{js,jsx}',
+      '<rootDir>/src/**/?(*.)(spec|test).{js,jsx}',
     ],
     testEnvironment: 'node',
     testURL: 'http://localhost',
     transform: {
-      '^.+\\.(js|jsx|mjs)$': isEjecting
+      '^.+\\.(js|jsx)$': isEjecting
         ? '<rootDir>/node_modules/babel-jest'
         : resolve('config/jest/babelTransform.js'),
       '^.+\\.css$': resolve('config/jest/cssTransform.js'),
       '^.+\\.(graphql)$': resolve('config/jest/graphqlTransform.js'),
-      '^(?!.*\\.(js|jsx|mjs|css|json|graphql)$)': resolve(
+      '^(?!.*\\.(js|jsx|css|json|graphql)$)': resolve(
         'config/jest/fileTransform.js'
       ),
     },
     transformIgnorePatterns: [
-      '[/\\\\]node_modules[/\\\\].+\\.(js|jsx|mjs)$',
+      '[/\\\\]node_modules[/\\\\].+\\.(js|jsx)$',
       '^.+\\.module\\.(css|sass|scss)$',
     ],
     moduleNameMapper: {
       '^react-native$': 'react-native-web',
       '^.+\\.module\\.(css|sass|scss)$': 'identity-obj-proxy',
     },
-    moduleFileExtensions: [
-      'web.js',
-      'js',
-      'json',
-      'web.jsx',
-      'jsx',
-      'node',
-      'mjs',
-    ],
+    moduleFileExtensions: ['web.js', 'js', 'json', 'web.jsx', 'jsx', 'node'],
   };
   if (rootDir) {
     config.rootDir = rootDir;